A flue gas heat exchanger for medical waste incineration line
Patent Information
- Application Number
- CN202610926386.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-24
- Publication Date
- 2026-10-09
AI Technical Summary
然而，由于医废焚烧尾气中极高浓度的酸性气体和粉尘，尤其是高浓度的HCl在高温条件下几乎可以与所有的金属发生反应，形成具有低熔点和高蒸汽压的氯化物，极易导致烟气换热器尤其是烟气换热器焊点部位的穿孔泄漏
[0018]一、通过设置与焊接部位对应的浇筑腔，并在浇筑腔内填充浇注料对不锈钢钢管和不锈钢钢管连接弯头的焊接部位进行防护，有效避免医废焚烧烟气对焊接部位的侵蚀，提高烟气换热流道的抗烟气侵蚀性能，由于不锈钢管两端的连接部位不与烟气接触，从根本上避免连烟气换热流道接缝隙处的漏液。
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Figure CN122881067A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of medical waste incineration technology, and in particular to a flue gas heat exchanger for a medical waste incineration line. Background Technology
[0002] Medical waste, or medical waste for short, contains large amounts of viruses and bacteria, and is classified as heavily polluted hazardous waste, posing a significant threat to human health and the ecological environment. Currently, the main method for treating medical waste is centralized incineration. During incineration and pyrolysis, medical waste generates large amounts of acidic gases, resulting in extremely high concentrations of acidic pollutants in the exhaust gas, along with a large amount of dust, especially when medical sludge is co-incinerated; therefore, specialized exhaust gas treatment is necessary. Existing technologies commonly employ exhaust gas treatment processes in medical waste incineration systems, including: waste heat absorption, dry quenching, composite acid removal, baghouse dust collection, and wet acid removal; among these, waste heat absorption is achieved through a flue gas heat exchanger. However, due to the extremely high concentrations of acidic gases and dust in the medical waste incineration exhaust gas, especially high concentrations of HCl, which can react with almost all metals under high-temperature conditions to form chlorides with low melting points and high vapor pressures, this can easily lead to perforation and leakage in the flue gas heat exchanger, particularly at the weld joints.
[0003] Therefore, developing and designing a flue gas heat exchanger that can meet the requirements of tail gas treatment in medical waste incineration lines is of great practical significance. Summary of the Invention
[0004] The purpose of this invention is to provide a flue gas heat exchanger that is not easily corroded or perforated and can be used in the tail gas treatment line of medical waste incineration lines. This invention aims to solve one or more technical problems existing in the prior art and to provide at least one beneficial option or create conditions.
[0005] To achieve the above objectives, the present invention adopts the following technical solution.
[0006] A flue gas heat exchanger for a medical waste incineration line includes a heat exchanger housing and a flue gas heat exchange channel installed inside the heat exchanger housing. The heat exchanger housing has a flue gas inlet and a flue gas outlet. The flue gas heat exchange channel includes several stainless steel pipes and stainless steel connecting elbows. Adjacent stainless steel heat exchange pipes are connected by corresponding stainless steel connecting elbows to form the flue gas heat exchange channel. A casting cavity is provided on the heat exchanger housing. The casting cavity is positioned at both ends of the stainless steel pipes and surrounds the welding points between the stainless steel connecting elbows and the stainless steel pipes. Castable refractory fills the casting cavity to encapsulate all welding points.
[0007] In a preferred embodiment, both ends of the stainless steel pipe extend outside the shell of the heat exchanger housing, and the casting cavity is installed on the outer wall of the heat exchanger housing; this facilitates the formation of the casting cavity and the subsequent casting of the refractory material. Alternatively, the casting cavity can also be located inside the heat exchanger housing.
[0008] In a preferred embodiment, the casting cavity surrounds the entire stainless steel connecting elbow, which reduces the connection gap between the casting cavity and the flue gas heat exchange channel, and better prevents flue gas from intruding into the casting cavity.
[0009] More preferably, the surfaces of the stainless steel pipe and the stainless steel connecting elbow are both subjected to pickling and passivation treatment, which is performed before assembling the stainless steel pipe and the stainless steel connecting elbow.
[0010] In one embodiment, the pickling and passivation treatment is performed after the stainless steel pipe and the stainless steel connecting elbow are assembled.
[0011] The pickling and passivation process is as follows: 1) Clean the stainless steel pipe and the stainless steel connecting elbow with an acidic cleaning agent; 2) Polish and grind the cleaned stainless steel pipe and the stainless steel connecting elbow; 3) Perform acid passivation treatment on the polished stainless steel pipe and the stainless steel connecting elbow with an acidic passivating agent; 4) Clean the acid-passivated stainless steel pipe and the stainless steel connecting elbow with an alkaline solution to neutralize and remove residual acid from the surface; 5) After the acid solution is neutralized and removed, clean the stainless steel pipe again with hot pure water, air dry it, and place it in a ventilated area to form a dense oxide film.
[0012] More preferably, the heat exchanger housing has a first flue gas heat exchange chamber and a second flue gas heat exchange chamber that are arranged vertically and communicate with each other. The flue gas inlet is connected to the first flue gas heat exchange chamber located on the lower side, and the flue gas outlet is connected to the second flue gas heat exchange chamber located on the upper side.
[0013] In one embodiment, the stainless steel tube located inside the first flue gas heat exchanger undergoes secondary anti-corrosion treatment.
[0014] In one embodiment, the secondary anti-corrosion treatment is to apply Teflon anti-corrosion treatment to the surface of the stainless steel pipe, and the thickness of the Teflon anti-corrosion layer is between 10-50 μm.
[0015] In one embodiment, the inner wall of the first flue gas heat exchange chamber is provided with a Teflon anti-corrosion layer, the thickness of which is between 10-50 μm.
[0016] In one embodiment, the heat exchanger housing is made of carbon steel, and the surface of the heat exchanger housing is sprayed with high-temperature silver paint.
[0017] Compared with the prior art, the flue gas heat exchanger for medical waste incineration lines provided by the present invention has at least the following beneficial effects:
[0018] 1. By setting up a casting cavity corresponding to the welding part and filling the casting cavity with castable material, the welding parts of stainless steel pipes and stainless steel pipe connecting elbows are protected, which effectively avoids the corrosion of the welding parts by medical waste incineration flue gas and improves the resistance of flue gas heat exchange channel to flue gas corrosion. Since the connection parts at both ends of the stainless steel pipe do not come into contact with the flue gas, leakage at the joint of the flue gas heat exchange channel is fundamentally avoided.
[0019] Second, the flue gas heat exchange channel is made of pickled and passivated stainless steel, which effectively improves the overall corrosion resistance of the flue gas heat exchanger and avoids leakage at the non-welded parts of the stainless steel pipe.
[0020] Third, by setting up two flue gas heat exchange chambers, during operation, the high-temperature flue gas with a large amount of dust first contacts the flue gas heat exchange channel located in the first flue gas heat exchange chamber, and then enters the second heat exchange chamber located downstream of the flue gas flow. In this way, the first flue gas heat exchanger can be subjected to secondary anti-corrosion treatment separately, which can not only ensure the overall anti-corrosion effect of the product, but also reduce the heat exchange efficiency loss caused by secondary anti-corrosion.
[0021] It should be noted that, in addition to the beneficial effects described above, other beneficial effects of the technical solution provided by this invention will become more apparent in the following description or be learned through practice. Attached Figure Description
[0022] Figure 1 The diagram shown is a structural schematic of the flue gas heat exchanger of the present invention.
[0023] Figure 2 The diagram shown is a schematic representation of the internal structure of the flue gas heat exchanger in this invention.
[0024] Explanation of the reference numerals in the attached figures.
[0025] 1: Heat exchanger housing; 2: Flue gas heat exchange channel; 3: Casting cavity.
[0026] 101: Flue gas inlet, 102: Flue gas outlet, 103: First flue gas heat exchange chamber, 104: Second flue gas heat exchange chamber.
[0027] 201: Stainless steel pipe; 202: Stainless steel connecting elbow. Detailed Implementation
[0028] The embodiments described in the following detailed description are not intended to limit the invention. Other embodiments and changes may be made without departing from the spirit or scope of the subject matter presented herein.
[0029] Although the present invention has been described in accordance with the best mode for achieving its objectives, those skilled in the art will recognize that several modifications may be made based on the teachings herein without departing from the spirit or scope of the invention.
[0030] Reference Figure 1 , Figure 2 As shown, a flue gas heat exchanger for a medical waste incineration line includes a heat exchanger housing 1 and a flue gas heat exchange channel 2 installed within the heat exchanger housing 1. The heat exchanger housing 1 has a flue gas inlet 101 and a flue gas outlet 102. The flue gas heat exchange channel 2 includes several stainless steel pipes 201 and stainless steel connecting elbows 202. Adjacent stainless steel heat exchange pipes 201 are connected by corresponding stainless steel connecting elbows 202 to form the flue gas heat exchange channel 2. The surfaces of the stainless steel pipes 201 and the stainless steel connecting elbows 202 are all subjected to pickling and passivation treatment, and refractory material is applied at the connection points between the stainless steel pipes 201 and the stainless steel connecting elbows 202.
[0031] The castable is a lightweight insulating castable resistant to temperatures above 1000℃, and its loss on ignition at 1000℃ is no more than 2wt%. In this embodiment, the castable contains 43.96% Al2O3, 42.61% SiO2, 1.02% Fe2O3, 10.28% CaO, 0.17% MgO, 0.72% K2O, 0.30% Na2O, and 0.94% TiO2, totaling 100%; the loss on ignition of this castable at 1025℃ is 1.92%. Obviously, those skilled in the art can make appropriate adjustments to the content of each component in the castable according to different actual needs. In some embodiments, the component ratio of the castable is adjusted within the following range: 40-45% Al2O3, 40-45% SiO2, 0.5-2% Fe2O3, 8-15% CaO, 0.1-0.5% MgO, 0.5-1.0% K2O, 0.1-0.5% Na2O and 0.5-1.0% TiO2.
[0032] Compared with the prior art, the flue gas heat exchanger for medical waste incineration line provided by the present invention uses pickled and passivated stainless steel material to prepare the flue gas heat exchange channel 2, and performs casting treatment at the elbow connection of the stainless steel pipe. This not only effectively improves the flue gas heat exchange channel's resistance to flue gas corrosion, but also ensures that the connection parts (each welded part) at both ends of the stainless steel do not come into contact with the flue gas, effectively reducing the corrosion of the elbow connection by the flue gas and avoiding leakage at the connection gap.
[0033] In this embodiment, the pickling and passivation treatment is performed before assembling the stainless steel pipe 201 and the stainless steel connecting elbow 202. The specific process is as follows: 1) Clean the stainless steel pipe 201 and the stainless steel connecting elbow 202 with an acidic cleaning agent; the pickling solution is a mixed aqueous solution of HNO3 and HF, with an HNO3 concentration of 10-15wt% and an HF concentration of 0.5-1wt%, and the pickling time is 3-5 minutes; 2) Polish and grind the cleaned stainless steel pipe 201 and the stainless steel connecting elbow 202; 3) Perform acid passivation treatment on the polished and ground stainless steel pipe 201 and the stainless steel connecting elbow 202 with an acidic passivating agent; the acidic passivating agent is HNO3 and K2C. r2 A mixed aqueous solution of O7, HNO3 concentration of 10-15 wt%, K2C r2 The O7 concentration is 1-3wt%, and the passivation time is 25-30min. 4) Clean the acid-passivated stainless steel pipe 201 and stainless steel connecting elbow 202 with alkaline solution to neutralize and remove the residual acid on the surface; 5) After the acid solution is neutralized and removed, clean the stainless steel pipe again with hot pure water, air dry it and place it in the vent to form a dense oxide film.
[0034] In some embodiments, the pickling and passivation treatment is performed after the stainless steel pipe 201 and the stainless steel connecting elbow 202 are assembled, as long as it can achieve the corresponding acid passivation and improve the corrosion resistance of the flue gas heat exchange channel 2.
[0035] To facilitate the application of the castable refractory, a casting cavity 3 is preferably provided on the heat exchanger housing 1. The casting cavity 3 is positioned corresponding to the joints at both ends of the stainless steel pipe 201 and surrounds the stainless steel connecting elbow 202. This way, when the castable refractory fills the casting cavity 3, all welded areas can be completely enclosed, preventing fumes from corroding the welded areas. In this embodiment, both ends of the stainless steel pipe 201 extend outside the shell of the heat exchanger housing 1, and the casting cavity 3 is installed on the outer wall of the heat exchanger housing 1. This facilitates the connection between the stainless steel connecting elbow 202 and the stainless steel pipe 201, and also facilitates the casting process. In some embodiments, the casting cavity 3 may be located inside the heat exchanger housing 1, or it may be formed by dividing the inner cavity of the heat exchanger housing 1; this is not limited to this embodiment.
[0036] Combined Figure 2As shown, in this embodiment, the heat exchanger housing 1 has a first flue gas heat exchange chamber 103 and a second flue gas heat exchange chamber 104 that are arranged vertically and communicate with each other. The flue gas inlet 101 is connected to the bottom of the first flue gas heat exchange chamber 103 located on the lower side, and the flue gas outlet 102 is connected to the top of the second flue gas heat exchange chamber 104 located on the upper side. The advantage of setting two flue gas heat exchange chambers is that, since the flue gas temperature in the first flue gas heat exchange chamber 103 is higher and the flue gas temperature in the second heat exchange chamber is lower, and the first flue gas heat exchange chamber 103 is located upstream of the flue gas flow, the heat exchanger housing 1 is divided into a high-temperature zone that is more easily corroded by acidic gases, dust, etc. in the flue gas and a low-temperature zone that is not easily corroded. By performing secondary anti-corrosion treatment on the stainless steel pipe 201 located in the high-temperature zone, the overall service life of the product can be further improved.
[0037] The secondary anti-corrosion treatment is preferably a Teflon anti-corrosion treatment applied to the surface of stainless steel, and the thickness of the Teflon anti-corrosion layer is preferably 30 μm. In some embodiments, the thickness of the Teflon anti-corrosion layer is appropriately selected between 10-50 μm. Since the Teflon anti-corrosion layer is only applied to the stainless steel tube 201 located in the first flue gas heat exchange chamber 103, this ensures the overall corrosion resistance of the product while avoiding the problem of reduced heat exchange efficiency caused by adding a Teflon anti-corrosion layer.
[0038] Furthermore, a Teflon anti-corrosion layer is also provided on the inner wall of the first flue gas heat exchange cavity 103. The thickness of the Teflon anti-corrosion layer is appropriately selected between 10-50μm to improve the corrosion resistance of the first flue gas heat exchange cavity 103.
[0039] In some embodiments, the heat exchanger housing 1 is made of carbon steel, which has a relatively low application cost. To improve the resistance of the heat exchanger housing 1 to flue gas corrosion, it is preferable to spray high-temperature silver paint on the surface of the carbon steel.
[0040] It should also be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0041] In this invention, unless otherwise specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "below," and "over" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Above," "below," and "below" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0042] Based on the above description of the structure and principles, those skilled in the art should understand that this invention is not limited to the specific embodiments described above. Improvements and substitutions made using techniques known in the art based on this invention all fall within the scope of protection of this invention, which should be defined by the claims and their equivalents. Parts not described in the specific embodiments are all prior art or common knowledge.
Claims
1. A flue gas heat exchanger for a medical waste incineration line, comprising a heat exchanger housing and a flue gas heat exchange channel installed within the heat exchanger housing, wherein the heat exchanger housing is provided with a flue gas inlet and a flue gas outlet, and the flue gas heat exchange channel comprises a plurality of stainless steel pipes and stainless steel connecting elbows, wherein adjacent stainless steel heat exchange pipes are connected by corresponding stainless steel connecting elbows to form the flue gas heat exchange channel; characterized in that, A casting cavity is provided on the heat exchanger housing. The casting cavity is provided at both ends of the stainless steel pipe and surrounds the welding parts of the stainless steel connecting elbow and the stainless steel pipe. The casting refractory fills the casting cavity and wraps all the welding parts.
2. The flue gas heat exchanger for a medical waste incineration line according to claim 1, characterized in that, Both ends of the stainless steel pipe extend through the outer shell of the heat exchanger housing, and the casting cavity is installed on the outer wall of the heat exchanger housing.
3. The flue gas heat exchanger for a medical waste incineration line according to claim 1, characterized in that, The casting cavity is located inside the heat exchanger box.
4. A flue gas heat exchanger for a medical waste incineration line according to claim 1, 2, or 3, characterized in that, The casting cavity surrounds the entire stainless steel connecting elbow.
5. A flue gas heat exchanger for a medical waste incineration line according to claim 1, characterized in that, The surfaces of the stainless steel pipe and the stainless steel connecting elbow are both subjected to pickling and passivation treatment, which is performed before the stainless steel pipe and the stainless steel connecting elbow are assembled. Alternatively, the pickling and passivation treatment is performed after the stainless steel pipe and the stainless steel connecting elbow are assembled.
6. A flue gas heat exchanger for a medical waste incineration line according to claim 1 or 5, characterized in that, The pickling and passivation process is as follows: 1) Cleaning the stainless steel pipe and the stainless steel connecting elbow with an acidic cleaning agent; 2) Polishing and grinding the cleaned stainless steel pipe and the stainless steel connecting elbow; 3) Performing acid passivation treatment on the polished stainless steel pipe and the stainless steel connecting elbow with an acidic passivating agent. 4) Clean the acid-passivated stainless steel pipe and stainless steel connecting elbow with an alkaline solution to neutralize and remove residual acidity from the surface. 5) After acid neutralization and removal, the stainless steel pipe is rinsed again with hot pure water, air-dried, and placed in a ventilated area to form a dense oxide film.
7. A flue gas heat exchanger for a medical waste incineration line according to claim 1, characterized in that, The heat exchanger housing has a first flue gas heat exchange chamber and a second flue gas heat exchange chamber that are arranged vertically and communicate with each other. The flue gas inlet is connected to the first flue gas heat exchange chamber located on the lower side, and the flue gas outlet is connected to the second flue gas heat exchange chamber located on the upper side.
8. A flue gas heat exchanger for a medical waste incineration line according to claim 7, characterized in that, The stainless steel tube located inside the first flue gas heat exchanger undergoes secondary anti-corrosion treatment.
9. A flue gas heat exchanger for a medical waste incineration line according to claim 8, characterized in that, The secondary anti-corrosion treatment involves applying Teflon anti-corrosion treatment to the surface of the stainless steel pipe, with the thickness of the Teflon anti-corrosion layer being between 10-50 μm.
10. A flue gas heat exchanger for a medical waste incineration line according to claim 7, characterized in that, The inner wall of the first flue gas heat exchange chamber is provided with a Teflon anti-corrosion layer, the thickness of which is between 10-50 μm.